jimmy mad Posted January 13, 2008 Share Posted January 13, 2008 I took my head off last night to hunt out my low compression problem and found a 5mm by 1 mm round the edge of no. 3 piston had chipped off and there is damage to the the bore that is adjacent to no.4 and 4 bore shows very bad damage and scouring with signs of pick up which has badly damaged the bore and left signs of seazing but the bores on piston 1 and 2 are like new no marks on bore and no signs of wear, its like a new engine. Wondered if any one has any ideas or come accross this before. I also have 2 leaking valves but not too bad. Any advice on what normally causes this will be greatly appreciated. Quote Link to comment Share on other sites More sharing options...
Les Henson Posted January 13, 2008 Share Posted January 13, 2008 damage to the the bore that is adjacent to no.4 and 4 bore shows very bad damage and scoreing and signs of pick up and seazing marks Can't understand that - is there supposed to be a 3 in there somewhere? Les. Quote Link to comment Share on other sites More sharing options...
jimmy mad Posted January 13, 2008 Author Share Posted January 13, 2008 changed it now dose it make more sense now chears les Quote Link to comment Share on other sites More sharing options...
western Posted January 13, 2008 Share Posted January 13, 2008 possibly a broken piston rings in each cylinder has caused the piston & bore damage in both 3 & 4 Quote Link to comment Share on other sites More sharing options...
jimmy mad Posted January 13, 2008 Author Share Posted January 13, 2008 i have now completely striped engine ready for rebore and the rings are ok the piston is badly scored as it the bore Quote Link to comment Share on other sites More sharing options...
western Posted January 13, 2008 Share Posted January 13, 2008 maybe the bit thats broken off has caused the damage in 3 then, no idea why 4 is damaged if everything is intact. Quote Link to comment Share on other sites More sharing options...
jimmy mad Posted January 13, 2008 Author Share Posted January 13, 2008 the bit that is most strange is that the piston and bore 4 show sings of seazing there is witness marks of the piston picking up on the barrel witch indictate it was seazing but not on any other bpre or piston dont under stand it Quote Link to comment Share on other sites More sharing options...
jimmy mad Posted January 13, 2008 Author Share Posted January 13, 2008 dose any one have a rough idea of how much a rebore on 4 bores would be ???? Quote Link to comment Share on other sites More sharing options...
western Posted January 13, 2008 Share Posted January 13, 2008 Les H, has recently had his 300 block done, so he should be able to give a fair idea. Quote Link to comment Share on other sites More sharing options...
Les Henson Posted January 14, 2008 Share Posted January 14, 2008 I paid £127 for the rebore. The engineers need to measure the bores first to determine what size pistons you will need to get. There are a variety of manufacturers of pistons - including 'white box' ones, which have no manufacturers name on. You can pay as little as £40 for one piston assembly, or buy genuine, which cost around £60 each. Les. Quote Link to comment Share on other sites More sharing options...
JimAttrill Posted January 14, 2008 Share Posted January 14, 2008 We get our blocks resleeved, which costs a bit extra, but then the OEM KS std pistons are much cheaper than the oversizes and are always easily available. Quote Link to comment Share on other sites More sharing options...
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